Activation of bystander CD8 + T cells in a pediatric patient with acute hepatitis E

• Published in: Immunological medicine pp. 1 - 7
• Main Authors: Morita, Atsushi, Imagawa, Kazuo, Iwasaki, Tomoya, Yaita, Katsuyuki, Sakai, Aiko, Takada, Hidetoshi
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 16.07.2024
• Subjects: Complementary determining region 3; cytokine; human leukocyte antigen; T cell receptor; Th1; cytokine; Complementary determining region 3; T cell receptor; Th1; human leukocyte antigen
• ISSN: 2578-5826; 2578-5826
• DOI: 10.1080/25785826.2024.2378542

Most children with acute hepatitis A virus (HAV) or hepatitis E virus (HEV) infection are asymptomatic. Bystander CD8 T-cell activation has garnered attention owing to its possible pathophysiological role in adult hepatitis. However, no reports have studied it in pediatric hepatitis. Herein, we describe the case of a three-year-old girl with acute hepatitis by HEV genotype 1. She had a history of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections, and HEV hepatitis occurred shortly after asymptomatic HAV infection. Peripheral immunophenotyping revealed activation of non-HEV-specific CD8 T cells which include EBV-specific and CMV-specific CD8 T cells, during the acute phase. While alanine-aminotransferase levels declined after admission, the total number of activated CD8 T cells increased for four days after admission and decreased thereafter. In contrast, activation of EBV-specific and CMV-specific CD8 T cells was almost at the maximal level at the time of admission, which suggest development of activated bystander CD8 T cells in the early stage. This case highlights the significance of the bystander CD8 T-cell activation even in pediatric hepatitis and the size of the CD8 T cell memory pool in the individuals for the development of hepatitis, given the patient's history of infections with EBV, CMV and HAV.